TYPO3 v9 has reached its end-of-life September 30th, 2021 and is not maintained by the community anymore. Looking for a stable version? Use the version switch on the top left.
You can order Extended Long Term Support (ELTS) here: TYPO3 ELTS.
Documentation is typically stored in reST files.
Directory and File Names¶
Files have the ending
Language files are located in the directory
Use spaces, not TABs.
Indent with 3 spaces per indent level.
See Setup IDE / Editor in this manual for information about setting up your Editor / IDE to adhere to the coding guidelines.